The invention relates to a process for demulsifying an emulsion. An emulsion consists of two immiscible liquid phases in which one liquid forms a dispersed phase of minute droplets suspended in the continuous phase of the other liquid. In time, the dispersed phase of the emulsion will coalesce to also form a continuous phase. At this time, the emulsion will no longer exist but is replaced by two continuous phases separated by a single interface. The time necessary for the emulsion to demulsify can be many years, depending on the emulsifier contained in the emulsion and the viscosities of the two phases in the emulsion. Many industrial processes require the demulsification of an emulsion, for example, the processing of crude oil may require the removal of emulsified water.
It is often desirable during an industrial process to create an emulsion that is very stable with respect to the separation of the phases, e.g. emulsions used in liquid membrane processes. However, this stability against separation makes it difficult to intentionally demulsify the emulsion if it is necessary to do so at a later stage in the industrial process. No general rule exists for demulsifying an emulsion. Several methods have been tried with varying degrees of success, depending on the emulsifier contained in the emulsion. However, the standard methods work less well or not at all as the emulsion becomes more stable. The standard methods include settling, heating, electrical coalescence and precipitation, centrifugation, filtration, use of chemicals or combinations thereof. For example, U.S. Pat. No. 2,338,986 discloses the demulsification of the emulsion that collects at the interface when an oil and water dispersion is allowed to settle. The emulsion is demulsified by combining with water and agitated by pumping the combination through a centrifugal pump or a restricted orifice. However, this method doesn't work for a very stable emulsion. The present invention provides a new means for breaking very stable emulsions.